This chapter includes detailed review of the research undertaken with conducting polymer (CP) based composites with chitosan (Ch) for tissue engineering till date. The beneficial role of electrically conductive biomaterials has been discussed with the possible strategies to overcome the shortcomings of CP alone through blending with Ch due to its excellent biocompatibility, biodegradability, and bioactivity. Additionally, this embodiment deals with the optimization and characterization of electrically conductive, biocompatible and biodegradable Polyaniline: Chitosan (PAni:Ch) nanocomposites as cell culture substrates for MDA-MB-231 and NIH 3T3 fibroblast in order to examine the combined effect of nanofiber structure and surface modification on cell-biomaterial interactions. The nanocomposites were further checked as a conductive scaffold for electrical stimulation of a neuronal model PC12 cell line in order to explore the potential of the materials in neural tissue engineering.
TopIntroduction
Tissue engineering is an interdisciplinary field that applies the principles and innovations from engineering and life-sciences toward the development of biological substitutes that restore, maintain or improve tissue function (Vacanti & Langer, 1999; Olson, Atala, & Yoo, 2011; Howard, Buttery, & Shakesheff, 2008). In recent years, the multidisciplinary knowledge obtained from micro and nanoscience and technology are being also involved in tissue engineering (Ratner, 2004). Typically, three approaches are investigated singularly or in combination: cells that create tissue, biomaterial scaffolds that give structural support to cells, and growth factors and cell-matrix (scaffold) interactions to create an environment that promotes the regeneration of functional tissues and organs. Therefore, one of the basic and sensitive strategies of the tissue engineering is the selection and construction of a biomaterial scaffold with the desired features in the design and fabrication of neotissues/organs. International Union of Pure and Applied Chemistry (IUPAC) defined biomaterial as a material exploited in contact with living tissues, organisms or microorganisms (Vert, Doi, & Hellwich, 2012). Biomaterials facilitate exciting new opportunities for repairing and reconstruction of damaged tissues by fabrication of biomimetic, biocomposite scaffolds upon which new cells can regenerate in vivo. Therefore, the ideal biomaterial should be biocompatible, biodegradable, highly porous with a large surface area to volume ratio, mechanically strong and capable of being formed into desired shapes. The biomaterial should possess appropriate surface properties to favor cellular attachment, proliferation, and differentiation (Yang, Leong, & Du, 2001). Moreover, the biomaterial scaffold should degrade at the rate of tissue formation as the cells synthesize natural matrix structure around themselves, the scaffold shall provide structural integrity within the body and eventually break down leaving the neo-tissue.
Since the first use of biomaterial based medical devices on human in the late 1940s and early 1950, the biomaterials field has acquired widespread scientific and technological applications such as cardiovascular prostheses, intraocular lenses, joint replacements, dental implants, scaffolds for in vivo and in vitro cell growth, skin substitutes, sutures, blood bags, bone cement, etc. (Ratner, Hoffman, & Schoen, 2004). With the advancement in the last few decades in areas such as medicine, cell and molecular biology, chemistry, materials science and engineering, biomaterials research has significantly evolved. The stages of development of biomaterials research can be classified in three generations, where each generation differs from the previous one by the specific purpose it tries to accomplish, thus enlarging the field of applications, and temporal overlapping can occur. Till now, the field is continuously updating with the design of novel biomaterials and emerging technologies.